Chapter 4 Flashcards
(18 cards)
What is blood composed of ?
- Plasma
- red blood cells
- white blood cells
- platelets
What is the function of plasma ?
Transports all blood cells and other substances around the body:
-Urea formed in liver is carried to kidneys where it is removed from your blood to form urine
What is the function of red blood cells ?
Biconcave disk coupled with haemoglobin gives the cell the ability to carry oxygen around the body
What is the function of White blood cells ?
Part of the body’s defense system and composed of:
- Lymphocytes, form antibodies against microorganism
- Phagocytes, engulf and digest invading bacteria and viruses
What is the function of Platelets ?
Small fragments of cells that have no nucleus, they clot blood at the site of a wound to prevent infections, the clot eventually dries and form a scab
Describe the 3 blood vessels
Arteries:
-Thick layer of muscle and elastic fibre, thick walls and small lumen. Carry oxygenated blood away from your heart to the organs of the body
Veins:
-Often have valves that prevent backflow of blood, carry blood away from the organs towards the heart. Have relatively thin walls, large lumen and often have valves
Capillary:
-link arteries and veins, have very thin walls (single cell thick) to enable substances such as oxygen and glucose toeasily diffuse out of blood and into cells, and a narrow lumen
Name and describe the human type of circulatory system
Double circulatory system:
- One transport system carries blood from the heart to the lungs and back to exchange oxygen and carbon dioxide
- Other transport system carries blood form your heart to all other organs of your body and back again
Describe how the Heart functions
- Deoxygenated blood flows through the Vena Cava into the right atrium, to the right ventricle and then is pumped out through the pulmonary artery where the blood is taken to the lungs
- The now oxygenated blood comes in through the pulmonary vein, into the left atrium and into the left ventricle, the oxygenated blood is then pumped through the aorta which where the blood is carried around the entire body
Describe 2 methods of helping faulty blood flow due to coronary heart disease
Stent:
-Stent balloon is put in place at the site of the fatty deposit
-Balloon is inflated to widen the blood vessel
-The balloon is extracted but stent remains and keeps the artery open
Statins:
-Reduce the amount of cholesterol levels which slows down the rate at which fatty material is deposited in the coronary arteries
Name 3 problems with the heart excluding coronary hart disease and how to help solve the problem
Leaky Valves:
-Insert artificial valves often made out of titanium and polymers, they last a very long time but require medicine to stop blood clots
-Biological valves from pigs, cattle and human donors may be used, this does not require any medication but only lasts around 12-15 years
Lack of regular rhythm:
-Pace makers keep the rhythm of the heart at a regular pace by using strong electrical signals
-If pacemakers fail for the patient, he/she may temporarily use an artificial heart however artificial hearts are not developed enough to be permanent
Describe the gas exchange system
Digestive organs are separated from the digestive organs by the diaphragm:
- Lungs ventilate air in and out by contraction and relaxation of intercostal muscles which change the pressure of the chest cavity so air is forced in or out of the lungs as a result of changing pressures
- The lungs maintain a steep concentration gradient because when you breathe in, oxygen rich air moves into your lungs, as a result oxygen continuously diffuses into your bloodstream through gas exchange surfaces of the alveoli, this maintains a steep concentration gradient so CO2 can continually diffuse out of the bloodstream and into the lungs
What is the purpose of the Epidermal tissue ?
Cover surface of plants to protect the leaf
What is the purpose of the Palisade Mesophyll layer ?
Contains lots of chloroplasts which carry out photosynthesis
What is the purpose of the spongy mesophyll tissue ?
Contains some chloroplasts however also has big air spaces and a large surface area to make diffusion of gasses easier
What is the purpose of the Xylem and Phloem ?
They are transport tissues in plants-
Xylem:
-Carries water and dissolved mineral ions from the roots up to the leaves
-Mature xylem cells are dead
Phloem:
-Carries dissolved food from the leaves around the plant
-Phloem is a living tissue
-The movement of the dissolved sugars is called translocation
Explain what factors and how they affect the rate of transpiration
Light:
-The stomata opens wider to allow more carbon dioxide into the leaf for photosynthesis, more water evaporates with this
Temperature:
-Rates of evaporation and diffusion increase due to the increased kinetic energy of particles
Wind:
-Water vapour is removed quickly by the air movement, increasing the rate of diffusion
Humidity:
-Diffusion of water slows down the greater the humidity due to the shift of the concentration gradient
Describe how we breath in and out
Breathing in:
-Ribs move up and out and diaphragm flattens, volume of the chest increases
-Increased volume means lower pressure in the chest
-Atmospheric air is at a higher pressure than the chest so air is drawn into the lungs
Breathing out:
-Ribs fall and diaphragm moves up, the volume of the chest decreases
-Decreased volume of the chest means that the pressure has increased
-The pressure in the chest is higher than outside so the air is forced out of the lungs
How are lungs adapted for gas exchange ?
- They are made up of clusters of alveoli which have a large surface area
- Alveoli have a rich supply of blood capillaries, this maintains a concentration gradient in both directions
- The layer of cells between the blood in the capillaries and air in the lungs is only one cell thick
